l822 



HUMAN ANATOMY 



and the respiratory 7.5 mm. In the female the length is 17 mm., and the respective 

 parts measure 11.5 mm. and 5.5 mm. The elasticity of the vocal part, however, 

 allows it to stretch. The shape of the rima glottidis varies with the position of the 

 arytenoids, and the theoretically straight lines of its borders may both be approxi- 

 mated and drawn asunder, and, moreover, may be bent at the junction of the two 

 parts. 



The veyitricle or laryngeal sinus (ventriculus laryngis) is a pouch, lined with 

 mucous membrane, opening into the larynx between the true and false cords of each 

 side. The horizontal elliptical opening has a breadth (vertically) of from 3-6 mm. 

 As has been stated, the upper surface of the true cord slants downward and outward ; 

 but the ventricle is partly under cover of the false cord, around which it ascends. 

 The ascent may be due to an appendix of the veyitricle (Fig. 1551), which may be an 

 almost separate cavity connected with the front of the ventricle by a slit or an irregular 



Fig. 1 551. 



Glands 



FaT 



False vocal cord 



Lymphoid tissue 

 Vocal cord 



Thyro-arytenoid ^ 



muscle ^ ^' 



Thyroid cartilage 



Epiglottis 



Lymphoid tissue 



4 Fat 



^Glands 



*jVentricle 



Point at which 

 squamous epithe- 

 lium ends 



Lateral crico- 

 arytenoid muscle 



Cricoid cartilage 

 Frontal section of larynx, about middle of vocal cords. 



X3- 



t 



opening. Not rarely, however, it is without separation from the rest of the ventricle. 

 It may ascend to a height of 15 mm. from the bottom of the ventricle. These cavi- 

 ties are compressed laterally, and situated in the thickness of the wall of the larynx 

 proper, internal to the fossa pyriformis. According to Riidinger, the ventricles are 

 relatively much larger in the male. Occasionally cases of great over-development of 

 the ventricles are met with. They may even perforate the thyro-hyoid membrane. 

 This is analogous to the sacs of the anthropoid apes. Brosike ' has seen a median 

 pouch perforating the thyroid in the region of the vocal cords. A similar structure 

 occurs in the horse, ass, and mule. The function of the true cords is to change the 

 size and shape of the glottis both during respiration and phonation, and to cause 

 sound by their vibrations, which depend in part on their tension. When drawn into 



' Virchow's Archiv, Bd. xcviii., 1884. 



